Oh Ashley, I am so very sorry to hear that Thumper is having back issues. It is painful to see your babies hurting and not be able to snap your fingers and make it all better. What I gathered from your post is that this is a "THIS TOO SHALL PASS" situation an in a couple of weeks the worst should be over.
Apart from following your vet's instructions, the only thoughts I have would be to 1) try to be upbeat don't let your anxiety about the situation to relay to Thumper as dogs are very sensitive to our psyche and 2) maybe when you are chilling in your favorite place, give Thumper some extra cuddle time. Sending
and
to you guys.